Bring a large pot of water to a boil. Salt and then cook pasta until just 2 minutes under al dente. Reserve 1.5 cups of pasta water, then drain.
16 oz rigatoni
While the pasta is cooking, dice the shallots and slice the chorizo into coins.
7 oz Spanish chorizo, 1 small shallot diced
Chop the basil and set aside.
3 tablespoon chopped basil
In a large skillet over medium heat, add olive oil and let it heat up a bit. Cook chorizo for 2-3 minutes, flip and repeat until slightly crisp. Remove and set aside.
1 teaspoon olive oil
Add prawns to the same pan and cook 30 seconds per side. Add in ½ teaspoon of oregano and a pinch of salt.
1 lb prawns or shrimp, ½ teaspoon oregano for prawns
Add a bit more olive oil, then sauté shallots for 2–3 minutes. Add garlic and cook 30 seconds more.
2 garlic cloves minced
Stir in tomato paste, oregano, and red pepper flakes. Cook tomato paste down for 2–3 minutes until caramelized and a deep red hue.
1 teaspoon oregano, ½ teaspoon red pepper flakes, 2.5 tablespoon tomato paste
Pour in chicken stock and heavy cream. Simmer for a few minutes uncovered to thicken.
¾ cup heavy cream, 1 cup chicken stock
Turn the heat to low and add your grated Parmigiano Reggiano making sure to blend well.
1 cup freshly grated parmigiano reggiano
Return pasta, prawns, and chorizo to the pan. Add more grated cheese if needed, top with basil and stir until creamy, using pasta water to loosen the sauce as needed. If the sauce doesn't thicken see my FAQ section.
1.5 - 2 cups cups reserved pasta water, Salt to taste
Finish with chopped basil and serve hot.